Mercedes' bid to overturn the result of the Abu Dhabi Grand Prix on Sunday, which saw Red Bull's Max Verstappen's win the world championship, suffered a major blow when stewards rejected the first of their two protests.
Mercedes claimed that Verstappen overtook Hamilton during the safety car period at the end of the race, just prior to a last lap sprint that resulted in the Dutchman winning the race and the title.
Mercedes claimed that Verstappen was in breach of Article 48.8 of the "sporting regulations".
Red Bull argued that both cars were "on and off the throttle" and that there were "a million precedents" under safety car conditions where cars had pulled alongside and then moved back behind the car that was in front.
The stewards concluded that althougth Verstappen did briefly move in front of Hamilton, he was not in front at the end of the safety car period.
A second appeal concerning safety car procedure remains under consideration.
Hamilton had been coasting to victory, his eighth world title seemingly in the bag.
Four laps from the end, however, Nicholas Latifi crashed his Williams, bringing out the safety car and prompting Verstappen to make a pit stop for fresh tyres.
When racing resumed for the 58th and closing lap Verstappen barged past Hamilton to take the chequered flag and the title.
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